The Monarch Journey
A story of survival: The Monarch journey is remarkable
Published: Friday, September 02, 2011
The Monarch butterfly story is one of
amazing survival tied to nature’s grand plan for this gentle flutterer,
which is the best known of all North American butterflies, found from
Canada to Mexico.
Each fall, hundreds of millions of Monarch
butterflies migrate from the United States and Canada to overwintering
areas in Mexico and California where they wait out the winter until
conditions favor a return flight in the spring. The monarch migration is
truly one of the world’s greatest natural wonders, yet it is threatened
by habitat loss in North America — at the overwintering sites and
throughout the spring and summer breeding range as well.
Females
begin laying eggs right after their first mating, and both sexes will
mate several times during their lives. Adult generations live from two
to five weeks.
But here is the amazing part. Each year, the
Monarch final generation, which emerges in late summer and early fall,
has an additional job: To migrate to their overwintering grounds, either
in central Mexico for eastern Monarchs or in Baja California for
western Monarchs.
Butterflies and moths undergo complete
metamorphosis, in which there are four distinct stages: Egg, larva
(caterpillar), pupa, and adult. Monarch development from egg to adult is
completed in about 30 days.
Monarchs usually lay a single egg on
a plant (typically milkweed), often on the bottom of a leaf near the
top of the plant. It is difficult to tell just how many eggs each female
lays during her life, but the average is probably from 100 to 300. The
eggs hatch about four days after they are laid.
From the egg, the
insect grows into the caterpillar stage (larvae) with a voracious
appetite for the leaves of a milkweed plant with growth at an
astonishing rate.
Once, the caterpillar has gorged itself on
leaf, the insect seeks higher ground, hanging like a letter J and into
the pupa stage spinning a chrysalis where the metamorphosis magic really
happens. Within the chrysalis, the caterpillar turns into a butterfly,
eventually spreading its wings and starting the life cycle all over
again.
Monarchs need to obtain nourishment to maintain their body
and fuel it for flight. Nectar from flowers, which is about 20-percent
sugar, provides most of their adult food. Monarchs are not very picky
about the source of their nectar, and will visit many different flowers.
They use their vision to find flowers, but once they land on a
potential food source, they use taste receptors on their feet to find
the nectar.
Sources: University of Kansas Monarch Project and Wikipedia.